zero in (on something/someone)
/ˈzɪr·oʊ, ˈzi·roʊ/present tense zeroes, present participle zeroing, past tense and past participle zeroed— phrasal verb with zero verb
to direct all your attention to one thing:
We’ve zeroed in on the real problem – we don’t save enough money.
If you zero in a weapon, you aim it directly at something you want to hit:
Computers help the pilots to zero in on their targets.